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-rw-r--r--include/migration/vmstate.h45
-rw-r--r--migration/vmstate.c25
2 files changed, 66 insertions, 4 deletions
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index df463fd33d..efa0a1150e 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -143,6 +143,11 @@ enum VMStateFlags {
* to determine the number of entries in the array. Only valid in
* combination with one of VMS_VARRAY*. */
VMS_MULTIPLY_ELEMENTS = 0x4000,
+
+ /* A structure field that is like VMS_STRUCT, but uses
+ * VMStateField.struct_version_id to tell which version of the
+ * structure we are referencing to use. */
+ VMS_VSTRUCT = 0x8000,
};
typedef enum {
@@ -167,6 +172,7 @@ struct VMStateField {
enum VMStateFlags flags;
const VMStateDescription *vmsd;
int version_id;
+ int struct_version_id;
bool (*field_exists)(void *opaque, int version_id);
};
@@ -248,6 +254,25 @@ extern const VMStateInfo vmstate_info_qtailq;
vmstate_offset_array(_state, _field, uint8_t, \
sizeof(typeof_field(_state, _field)))
+/* In the macros below, if there is a _version, that means the macro's
+ * field will be processed only if the version being received is >=
+ * the _version specified. In general, if you add a new field, you
+ * would increment the structure's version and put that version
+ * number into the new field so it would only be processed with the
+ * new version.
+ *
+ * In particular, for VMSTATE_STRUCT() and friends the _version does
+ * *NOT* pick the version of the sub-structure. It works just as
+ * specified above. The version of the top-level structure received
+ * is passed down to all sub-structures. This means that the
+ * sub-structures must have version that are compatible with all the
+ * structures that use them.
+ *
+ * If you want to specify the version of the sub-structure, use
+ * VMSTATE_VSTRUCT(), which allows the specific sub-structure version
+ * to be directly specified.
+ */
+
#define VMSTATE_SINGLE_TEST(_field, _state, _test, _version, _info, _type) { \
.name = (stringify(_field)), \
.version_id = (_version), \
@@ -395,6 +420,17 @@ extern const VMStateInfo vmstate_info_qtailq;
.offset = offsetof(_state, _field), \
}
+#define VMSTATE_VSTRUCT_TEST(_field, _state, _test, _version, _vmsd, _type, _struct_version) { \
+ .name = (stringify(_field)), \
+ .version_id = (_version), \
+ .struct_version_id = (_struct_version), \
+ .field_exists = (_test), \
+ .vmsd = &(_vmsd), \
+ .size = sizeof(_type), \
+ .flags = VMS_VSTRUCT, \
+ .offset = vmstate_offset_value(_state, _field, _type), \
+}
+
#define VMSTATE_STRUCT_TEST(_field, _state, _test, _version, _vmsd, _type) { \
.name = (stringify(_field)), \
.version_id = (_version), \
@@ -712,6 +748,13 @@ extern const VMStateInfo vmstate_info_qtailq;
#define VMSTATE_SINGLE(_field, _state, _version, _info, _type) \
VMSTATE_SINGLE_TEST(_field, _state, NULL, _version, _info, _type)
+#define VMSTATE_VSTRUCT(_field, _state, _vmsd, _type, _struct_version)\
+ VMSTATE_VSTRUCT_TEST(_field, _state, NULL, 0, _vmsd, _type, _struct_version)
+
+#define VMSTATE_VSTRUCT_V(_field, _state, _version, _vmsd, _type, _struct_version) \
+ VMSTATE_VSTRUCT_TEST(_field, _state, NULL, _version, _vmsd, _type, \
+ _struct_version)
+
#define VMSTATE_STRUCT(_field, _state, _version, _vmsd, _type) \
VMSTATE_STRUCT_TEST(_field, _state, NULL, _version, _vmsd, _type)
@@ -1000,6 +1043,8 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque, int version_id);
int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
void *opaque, QJSON *vmdesc);
+int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
+ void *opaque, QJSON *vmdesc, int version_id);
bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque);
diff --git a/migration/vmstate.c b/migration/vmstate.c
index 0b3282c9df..f0b07f4ea1 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -136,6 +136,9 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
} else if (field->flags & VMS_STRUCT) {
ret = vmstate_load_state(f, field->vmsd, curr_elem,
field->vmsd->version_id);
+ } else if (field->flags & VMS_VSTRUCT) {
+ ret = vmstate_load_state(f, field->vmsd, curr_elem,
+ field->struct_version_id);
} else {
ret = field->info->get(f, curr_elem, size, field);
}
@@ -209,6 +212,8 @@ static const char *vmfield_get_type_name(VMStateField *field)
if (field->flags & VMS_STRUCT) {
type = "struct";
+ } else if (field->flags & VMS_VSTRUCT) {
+ type = "vstruct";
} else if (field->info->name) {
type = field->info->name;
}
@@ -309,7 +314,13 @@ bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque)
int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
- void *opaque, QJSON *vmdesc)
+ void *opaque, QJSON *vmdesc_id)
+{
+ return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id);
+}
+
+int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
+ void *opaque, QJSON *vmdesc, int version_id)
{
int ret = 0;
VMStateField *field = vmsd->fields;
@@ -327,13 +338,15 @@ int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
if (vmdesc) {
json_prop_str(vmdesc, "vmsd_name", vmsd->name);
- json_prop_int(vmdesc, "version", vmsd->version_id);
+ json_prop_int(vmdesc, "version", version_id);
json_start_array(vmdesc, "fields");
}
while (field->name) {
- if (!field->field_exists ||
- field->field_exists(opaque, vmsd->version_id)) {
+ if ((field->field_exists &&
+ field->field_exists(opaque, version_id)) ||
+ (!field->field_exists &&
+ field->version_id <= version_id)) {
void *first_elem = opaque + field->offset;
int i, n_elems = vmstate_n_elems(opaque, field);
int size = vmstate_size(opaque, field);
@@ -363,6 +376,10 @@ int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
} else if (field->flags & VMS_STRUCT) {
ret = vmstate_save_state(f, field->vmsd, curr_elem,
vmdesc_loop);
+ } else if (field->flags & VMS_VSTRUCT) {
+ ret = vmstate_save_state_v(f, field->vmsd, curr_elem,
+ vmdesc_loop,
+ field->struct_version_id);
} else {
ret = field->info->put(f, curr_elem, size, field,
vmdesc_loop);